Dividing Dahlias: Separate Tubers Any Time Now

Evé looks over a tuber mass, recently dug and rinsed.

In most parts of the country, frost has put an end to the last dahlia blooms of the season, and many of you have already dug your dahlias for winter storage.

Each dahlia tuber you planted has no doubt become a mass of new tubers, many of which have the potential for producing new plants like the ones you grew this year. Dividing your dahlias into individual tubers now will get them ready for safe storage this winter and for spring planting next season.

To find out how the pros divide dahlias, we spent some time with Lynch Creek Farm's go-to guy of the garden, Evé Munguia.

Here's Evé's advice, step by step, on making the most of that mass of dahlia tubers, roots, and rootlets you're storing.

Look for the tiny pointed eyes, like
the eyes of potatoes, where the tubers
connect to the central stem.

Keep in mind that every dahlia tuber, to be viable, must have at least one eye, which you'll see as tiny pointed protrusions on or near the neck of the tuber (the neck is the tuber's connection to the central part of the root mass).

Clip away the thin rootlets and
tubers without eyes.

1. Prepare for dividing your dahlias by putting together what you need. You'll want a good cutting board or countertop under nice strong light so you can see the eyes and make your cuts where they need to be. Your cutting implements should be clean and sharp. A pair of sharp long-nosed clippers is best, although some growers use knives. Assemble the dahlia clumps to be divided; they should be rinsed before dividing.

Cut the eyed tuber from the central stem making
a V into the central stem and leaving
a bit of the fleshy stemwood on the tuber neck.

2. Eliminate from the tuber mass the small roots, rootlets and stuff that doesn't have eyes.  Not all the tubers that form will have eyes, and tubers without eyes won't produce new plants. Also eliminate any tubers whose necks are wiggly or broken; they won't grow.

3. Identify the eyed tuber that's easiest to reach and remove with your clippers. If you're unfamiliar with eyes, look for a tiny point at the center of a rounded protrusion. Don't cut too close to the neck. Making a V-shaped cut into the central part of the tuber group will give your tuber more strength and stability.

The mother tuber will have coarser skin than new tubers.

4. Check out the "mother tuber," the one from which your plant grew this year. It is easy to identify because its skin is coarser and usually darker than the newly-grown tubers. If the mother tuber looks viable, with a significant eye and no signs of rot, it can be used again. Mother tubers are more susceptible to rot because of their size and age.

5. If a dahlia tuber without an eye or eyes is adjacent to an eyed tuber, and it's convenient to leave the two connected, do.  Often it will be hard to separate an eyed tuber and an adjacent eyeless tuber; there's no need to do so. The plant that comes from the eye will benefit from the early-season vigor provided by the additional tuber.

An eyed tuber and one without eyes can be paired to
give next year's shoots a good start.

6. Keep separating out eyed tubers until you have utilized all of them in the tuber mass. Shape isn't an issue; a long, skinny tuber, if it has a viable eye, will produce a plant. Under optimal conditions, a healthy, well-grown dahlia can produce a dozen or more tubers under optimal conditions.

Often when you dig your dahlias, your shovel will break off part of a tuber that extends beyond the main mass. Don't despair if the cut-off tuber is one of the eyed tubers; if there's a significant amount of flesh remaining, it will likely produce a new plant.  As long as the cut area is exposed to the air and allowed to dry after the dahlia has been dug, it will heal and harden.

And speaking of the cut surfaces of your divided dahlia tubers: you may be tempted to look for some kind of antibacterial or other powder to dust your tubers before storing them. If your tubers are healthy, they won't need it. Just store them in an appropriate medium. At Lynch Creek Farm, the crew uses peatmoss, very lightly dampened to maintain humidity.

Take good care of those tubers (see our September 25 blog), and next spring you'll have abundance for your garden and tubers to share. Be sure to give some to friends so you have room for new favorites from Lynch Creek Farm.